The present invention relates generally to ballasts used for driving fluorescent lamps, and more particularly, to a device for remotely detecting and indicating whether a ballast driving a fluorescent lamp is of the magnetic type.
Two different types of ballasts are presently being used to drive fluorescent lampsxe2x80x94magnetic and electronic. A magnetic ballast serves as a current regulator that controls the power delivered to a fluorescent lamp, whereas an electronic ballast is actually an AC-AC converter. In an electronic ballast, the 120/277V alternating current (AC) input is first rectified to a direct current (DC) signal, and then is converted into a much higher frequency (e.g., above 40 KHz) AC signal to drive the lamp.
With the same input power, a fluorescent lamp can deliver more light using higher frequency input signals, which means there is higher efficiency and conservation of energy. Moreover, a lamp generates no (or substantially less) flicker with a high frequency input. Therefore, since electronic ballasts provide better light quality and save energy, they have become more and more popular, and it has become desirable to replace magnetic ballasts with electronic ballasts.
Obviously, to replace a low efficiency magnetic ballast with a high efficiency electronic ballast, one must first identify the type of ballast utilized in a fluorescent lamp fixture. Once a ballast and lamp have been installed in a fixture, it is somewhat difficult to determine the type of ballast that has been employed. Typically, this determination requires an electrician to open the cover, remove the fluorescent lamps, take off the reflector and then determine the type of ballast that is being used. A more time-efficient and cost-efficient method for determining the type of ballast employed in a fluorescent lamp fixture is desired.
The invention provides such a method, and an apparatus for performing the method. To save both time and cost, the invention provides a means by which the type of ballast employed in a fluorescent lamp fixture can be determined remotely without disassembling or otherwise physically handling the fixture. In operation, a user simply holds the electronic devicexe2x80x94which includes a light sensorxe2x80x94under the fluorescent lamp (within approximately 3-10 feet) and pushes a start-up button. Within about three seconds, the electronic components in the device determine from the flicker frequency of the light emitted by the fluorescent lamp whether the employed ballast is of the magnetic type or not. In a preferred embodiment, if the ballast is determined to be magnetic, a first (e.g., green) light-emitting diode (LED) is illuminated for about five seconds. Otherwise, a second (e.g., red) LED is illuminated.
Accordingly, one object of the present invention is to provide an electronic device for remotely detecting and indicating whether the ballast driving a fluorescent lamp is of the magnetic type or not.
Another object of the present invention is to provide such a magnetic ballast detection device that is both small in size and portable.
A still further object of the present invention is to provide such a magnetic ballast detection device that has an inactive (xe2x80x9csleepxe2x80x9d) mode in which the electronic components consume very little energy, thus extending the life of an on-board power supply.
In accordance with a preferred embodiment of the present invention, there is provided a portable, electronic device for remotely detecting and indicating whether a ballast driving a fluorescent lamp is of the magnetic type, the device comprising a light sensor that receives emitted light from the fluorescent lamp and, in response, produces an output signal having a frequency proportional to the flicker frequency of the emitted light; a voltage detector, electrically coupled to the light sensor, that converts the output signal into a digital signal stream having a pulse frequency proportional to the frequency of the output signal; a microcontroller, electrically coupled to the voltage detector, that determines whether the pulse frequency of the digital signal stream is between predetermined high and low threshold levels, wherein a first indicator signal indicating the presence of a magnetic ballast is produced as a first output of the microcontroller when the pulse frequency of the digital signal stream is determined to be between the threshold levels; and at least one power supply for the light sensor, the voltage detector and the microcontroller.